Method and device for reliably monitoring a closed position of two parts moveable relative to one another

• US 20060181417A1
• Filed: 01/13/2006
• Published: 08/17/2006
• Est. Priority Date: 07/21/2003
• Status: Active Grant

• Current Assignee: PILZ GmbH & Company KG
• Original Assignee: PILZ GmbH & Company KG
• Inventors: Zinser, Christoph, Nitsche, Thomas, Pullmann, Juergen
• Granted Patent: US 7,548,159 B2
• Time in Patent Office: Days
• US Class Current: 340/545.200
• CPC Class Codes: F16P 3/08 in connection with the locking of doors, covers, guards, or like members giving access to moving machine parts
• CPC Class Codes: H03K 17/9502 Measures for increasing reliability
• CPC Class Codes: H03K 17/97 using a magnetic movable element
• CPC Class Codes: H03K 2017/9706 Inductive element
• CPC Class Codes: H03K 2217/958 involving transponders

Abstract

A device for reliably monitoring a closed position of two parts which can move relative to one another has an actuator and a sensor. The device is particularly used for monitoring the closed position of a protective door installed for safeguarding a technical installation which operates in an automated fashion. The sensor has a receiver circuit at an input side, which circuit generates a defined receiver circuit signal when a switching distance between the sensor and the actuator is fallen short of. A detector circuit provides an enable signal when the defined receiver circuit signal is present. According to one aspect of the invention, a test element is provided for selectively suppressing the defined receiver circuit signal.

Claims

1. A device for reliably monitoring a closed position of two parts moveable relative to one another, the device comprising an actuator and a sensor each for mounting to one of the parts, the sensor having a receiver circuit for generating a defined receiver circuit signal when a switching distance between the sensor and the actuator is fallen short of, further comprising a detector circuit for providing an enable signal when the defined receiver circuit signal is present, and comprising a test element designed to selectively suppress the defined receiver circuit signal.

2. The device of claim 1, wherein the test element is an electrical, electronic or optical switching element.

3. The device of claim 1, wherein the test element is arranged in the region of the receiver circuit.

4. The device of claim 1, wherein the receiver circuit comprises an inductor and a capacitor connected thereto, and wherein the test element is designed to isolate the inductor and the capacitor from one another electrically.

5. The device of claim 1, wherein the test element is designed to isolate the receiver circuit from the detector circuit.

6. The device of claim 1, wherein the actuator comprises a transponder element with information stored therein, and wherein the sensor is designed to read out the information using the receiver circuit when the switching distance is fallen short of.

7. The device of claim 6, wherein the sensor is designed to read out the information in a continuously repeated fashion when the switching distance is fallen short of.

8. The device of claim 5, wherein the detector circuit comprises a logic module which provides the enable signal only if the information from the actuator corresponds to predefined information.

9. The device of claim 8, wherein the detector circuit has an operating mode in which the logic module is configured to read in the predefined information.

10. The device of claim 1, further comprising an evaluation and control unit designed to suppress the first receiver circuit signal cyclically using the test element.

11. The device of claim 10, wherein the evaluation and control unit is spatially remote from the sensor.

12. The device of claim 1, wherein the detector circuit is integrated into the sensor.

13. The device of claim 1, wherein the detector circuit is of single-channel design.

14. The device of claim 1, wherein the two parts form a protective door for safeguarding a technical installation operating in an automated fashion.

15. A sensor for detecting the presence of an actuator mounted to a first part that is moveable relative to a second part, the sensor being adapted to be mounted to the second part and comprising a receiver circuit for generating a defined receiver circuit signal when the actuator comes close to the sensor, comprising a detector circuit for providing an enable signal when the defined receiver circuit signal is present, and comprising a test element designed to selectively suppress the defined receiver circuit signal.

16. A method for reliably monitoring a closed position of two parts moveable relative to one another, the method comprising the steps of:

arranging an actuator on one of the parts,

arranging a sensor having a receiver circuit on the other of the parts,

generating a defined receiver circuit signal using the receiver circuit if a switching distance between the sensor and the actuator is fallen short of,

generating an enable signal using a detector circuit if the defined receiver circuit signal is present, and

when the defined receiver circuit signal is present, briefly suppressing the defined receiver circuit signal using a test element and generating a monitoring message if the detector circuit does not react to the suppression of the defined receiver circuit signal.